EFFECTS OF TEMPERATURE AND LIGHT CONDITIONS ON FLOWER INITIATION AND FRUIT-DEVELOPMENT IN STRAWBERRY

Several experiments were carried out to develop a new cultivation syst em for strawberry suited to Japan's cooler regions to enable June-bear ing cultivars to produce high quality fruits in autumn: (1) Runner pla nts of cv. Nyoho were subjected to refrigerator-cooling, short-day cyc les or shading treatments. Flowering was successfully advanced to earl y August depending on the treatment conditions. Factors affecting the treatment effectiveness were analyzed. (2) The development of fruit in cv. Morioka-16 varied considerably with the day, night and mean diurn al temperature conditions. Fruit production with marketable value was not satisfactory at diurnal mean temperatures above 20 degrees C, and the yield was reduced when the day temperatures exceeded 25 degrees C. (3) Based on the results obtained, a new autumn cropping cultural sys tem was proposed and the procedure for determining the optimal time of the processes was outlined.